D.2 How To Protect The Et 200 Distributed I/O System Against Overvoltage - Siemens SIMATIC S5 Manual

The ET 200 distributed I/O system and lightning protection
D.2 How to protect the ET 200 distributed I/O system against
overvoltage
Rules for the 0 1
interface (potential
equalization in
lightning protec-
tion system)
D-4
Suitable measures for potential equalization in the lightning-protection
system at the interface between lightning-protection zones 0
follows:
Use twisted metal straps or metal braids of sufficient current-carrying
capacity as cable shields, e.g. NYCY or A2Y(K)Y, and ground these
straps at both ends;
or
lay the cables in
– continuously connected metal conduits grounded at both ends, or
– in reinforced-concrete ducts with continuous reinforcing members, or
– on enclosed cable trays made of metal and grounded at both ends.
or
use fiber-optic waveguides instead of lines which are capable of carrying
the surge current.
1 are as
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a